1. Technical Field
The present invention is directed to an apparatus for dense chip packaging using heat pipes and thermoelectric coolers.
2. Description of Related Art
Increasing power density in electronic circuits creates a need for improvements to systems for transferring heat away from the circuit. The power density increases as the level of integration and speed of operation increase. Therefore, as electronic circuits become more integrated and operational speeds increase, the need to transfer heat away from the circuits becomes of great importance.
Heat pipes can help improve heat rejection from integrated circuits. Micro-heat pipes use small ducts filled with a working fluid to transfer heat from high temperature devices. The ducts are typically straight channels, cut or milled into a surface. Evaporation and condensation of the fluid transfers heat through the duct. The fluid vaporizes in the heated region of the duct. The vapor travels to the cooled section of the duct, where it condenses. The condensed liquid collects in the corners of the duct, and capillary forces pull the fluid back to the evaporator region. The fluid is in a saturated state so the inside of the duct is nearly isothermal.
U.S. Pat. Nos. 5,769,154 and 5,947,183, which are hereby incorporated by reference, disclose a wick structure for distributing fluid within a heat pipe system. The wick structure allows fluid flow in multiple directions to thereby return fluid to heated regions. These wick structures, however, have high fluid resistance due to the wick structures having an arbitrary configuration, are not efficient in terms of transferring heat to the fluid, and are not flexible thus limiting the use of such wick structures to rigid applications. Therefore, it would be beneficial to have a heat pipe apparatus with improved capillary structures and vapor chambers to thereby improve the operational of the heat pipes. In addition, it would be beneficial to have a heat pipe apparatus that is flexible so that it can be used in a plurality of different implementations.
An apparatus for dense chip packaging using heat pipes and thermoelectric coolers is provided. The apparatus includes an evaporator region, a condenser region, and a capillary region. The evaporator region includes one or more hot point elements used to transfer heat from a heat source to a transport fluid. The transport fluid changes state to a vapor when heat is applied to the transport fluid. The vapor travels to the condenser region via vapor channels and is condensed to a fluid once again by transferring heat from the vapor to a heat sink. The condensed fluid is then returned to the evaporator region by way of capillary forces and capillaries formed in a capillary structure. The capillaries formed in the capillary structure have a tree-like or fractal geometry. The apparatus may further include a flexible region that allows the apparatus to be bent around corners and edges.